1. Field of the Invention
This invention relates to converting data into a tabular structure, and more particularly to formatting XML data into tabular structures
2. Background of the Invention
There are a number of difficulties in converting a rich hierarchical data format such as XML into a tabular structure. XML data contains several inherent types of information that are not directly convertible into tables, and the hierarchy, order, and type of each tabular element may be difficult to convert to a table.
Related prior art includes U.S. Pat. No. 6,704,744 to Williamson et al. which discloses a method and apparatus for mapping objects to multiple tables of a database.
Other art includes U.S. Pat. No. 6,799,182 to Bata which discloses a system and method for data source flattening; U.S. Pat. No. 6,832,219 to Lal which discloses a method and system for storing and querying of markup based documents in a relational database; U.S. Pat. No. 5,937,401 to Hillegas which discloses a database system with improved methods for filtering duplicates from a tuple stream; U.S. Pat. No. 5,295,256 to Bapat which discloses an automatic storage of persistent objects in a relational schema; U.S. Patent Application Publication No. 2003/0070144 to Schnelle et al. which discloses a method, an apparatus and a computer program product for converting an XML encoded dataset into a minimal set of SQL tables; U.S. Patent Application Publication No. 2001/0047372 to Gorelik et al. which discloses, in a data processing system, hierarchical documents or hierarchical messages that are mapped to a Nested Relational Data Model to allow for transformation and manipulation using declarative statements; U.S. Patent Application Publication No. 2005/0010896 to Meliksetian et al., which discloses a program product, system and method for transforming data between an XML representation and a relational database system wherein a mapping description is created in a mark-up language such as XML and XSL; U.S. Patent Application Publication No. 2004/0163041 to Engel, which discloses textual elements and unambiguous locations paths corresponding to textual elements and/or their ancestors that are extracted from a tree-structured document such as an XML document and stored in relational database structures; U.S. Patent Application Publication No. 2004/0064466 to Manikutty et al., which discloses techniques for executing database commands include receiving a database command that includes an XML component operation that operates on an XML construct that is based on a first set of one or more relational database constructs; U.S. Patent Application Publication No. 2003/0212664 Breining et al., which discloses an XML wrapper which queries an XML document in an on-the-fly manner so that only parent nodes in the document that satisfy the query are extracted and then unnested; and U.S. Patent Application Publication No. 2002/0099715 Jahnke et al., which discloses a method for importing data from an XML document containing a plurality of elements and a plurality of attributes into a relational database.
The prior art includes several ways of converting XML data into a tabular structure, but these tend to lack certain features. For example in many of the conversion processes, the conversion holds the entire document in memory at once, requiring a significant memory. In others, single columns cannot have multiple data sources, which doesn't allow for the intelligent import of similar yet differently-named and structured XML structures. In yet others, the specified data sources cannot be specific instances of XML elements, and in yet others the data sources cannot provide the name of the XML data source, as well as providing the data.